From: Alan Maguire <alan.maguire@oracle.com> mainline inclusion from mainline-v6.11-rc1 commit 47a8cf0c5b3f6769b9d558301735c75119a0a165 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8335 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- add simple kfuncs to create/destroy a context type to bpf_testmod, register them and add a kfunc_call test to use them. This provides test coverage for registration of dtor kfuncs from modules. By transferring the context pointer to a map value as a __kptr we also trigger the map-based dtor cleanup logic, improving test coverage. Suggested-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240620091733.1967885-7-alan.maguire@oracle.com Conflicts: tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h [The conflicts were due to some minor issue.] Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- .../selftests/bpf/bpf_testmod/bpf_testmod.c | 46 +++++++++++++++++++ .../bpf/bpf_testmod/bpf_testmod_kfunc.h | 9 ++++ .../selftests/bpf/prog_tests/kfunc_call.c | 1 + .../selftests/bpf/progs/kfunc_call_test.c | 37 +++++++++++++++ 4 files changed, 93 insertions(+) diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 2c5c64950781..700bba39a22c 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -138,6 +138,37 @@ __bpf_kfunc void bpf_iter_testmod_seq_destroy(struct bpf_iter_testmod_seq *it) it->cnt = 0; } +__bpf_kfunc struct bpf_testmod_ctx * +bpf_testmod_ctx_create(int *err) +{ + struct bpf_testmod_ctx *ctx; + + ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC); + if (!ctx) { + *err = -ENOMEM; + return NULL; + } + refcount_set(&ctx->usage, 1); + + return ctx; +} + +static void testmod_free_cb(struct rcu_head *head) +{ + struct bpf_testmod_ctx *ctx; + + ctx = container_of(head, struct bpf_testmod_ctx, rcu); + kfree(ctx); +} + +__bpf_kfunc void bpf_testmod_ctx_release(struct bpf_testmod_ctx *ctx) +{ + if (!ctx) + return; + if (refcount_dec_and_test(&ctx->usage)) + call_rcu(&ctx->rcu, testmod_free_cb); +} + struct bpf_testmod_btf_type_tag_1 { int a; }; @@ -343,8 +374,14 @@ BTF_KFUNCS_START(bpf_testmod_common_kfunc_ids) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_testmod_ctx_create, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_testmod_ctx_release, KF_RELEASE) BTF_KFUNCS_END(bpf_testmod_common_kfunc_ids) +BTF_ID_LIST(bpf_testmod_dtor_ids) +BTF_ID(struct, bpf_testmod_ctx) +BTF_ID(func, bpf_testmod_ctx_release) + static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = { .owner = THIS_MODULE, .set = &bpf_testmod_common_kfunc_ids, @@ -608,6 +645,12 @@ extern int bpf_fentry_test1(int a); static int bpf_testmod_init(void) { + const struct btf_id_dtor_kfunc bpf_testmod_dtors[] = { + { + .btf_id = bpf_testmod_dtor_ids[0], + .kfunc_btf_id = bpf_testmod_dtor_ids[1] + }, + }; int ret; ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_testmod_common_kfunc_set); @@ -615,6 +658,9 @@ static int bpf_testmod_init(void) ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_testmod_kfunc_set); ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_testmod_kfunc_set); ret = ret ?: register_bpf_struct_ops(&bpf_bpf_testmod_ops, bpf_testmod_ops); + ret = ret ?: register_btf_id_dtor_kfuncs(bpf_testmod_dtors, + ARRAY_SIZE(bpf_testmod_dtors), + THIS_MODULE); if (ret < 0) return ret; if (bpf_fentry_test1(0) < 0) diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h index f5c5b1375c24..9e0e6821539a 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h @@ -64,6 +64,11 @@ struct prog_test_fail3 { char arr2[]; }; +struct bpf_testmod_ctx { + struct callback_head rcu; + refcount_t usage; +}; + struct prog_test_ref_kfunc * bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr) __ksym; void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; @@ -104,4 +109,8 @@ void bpf_kfunc_call_test_fail1(struct prog_test_fail1 *p); void bpf_kfunc_call_test_fail2(struct prog_test_fail2 *p); void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p); void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len); + +struct bpf_testmod_ctx *bpf_testmod_ctx_create(int *err) __ksym; +void bpf_testmod_ctx_release(struct bpf_testmod_ctx *ctx) __ksym; + #endif /* _BPF_TESTMOD_KFUNC_H */ diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c index 2eb71559713c..5b743212292f 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c @@ -78,6 +78,7 @@ static struct kfunc_test_params kfunc_tests[] = { SYSCALL_TEST(kfunc_syscall_test, 0), SYSCALL_NULL_CTX_TEST(kfunc_syscall_test_null, 0), TC_TEST(kfunc_call_test_static_unused_arg, 0), + TC_TEST(kfunc_call_ctx, 0), }; struct syscall_test_args { diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c index cf68d1e48a0f..f502f755f567 100644 --- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c @@ -177,4 +177,41 @@ int kfunc_call_test_static_unused_arg(struct __sk_buff *skb) return actual != expected ? -1 : 0; } +struct ctx_val { + struct bpf_testmod_ctx __kptr *ctx; +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct ctx_val); +} ctx_map SEC(".maps"); + +SEC("tc") +int kfunc_call_ctx(struct __sk_buff *skb) +{ + struct bpf_testmod_ctx *ctx; + int err = 0; + + ctx = bpf_testmod_ctx_create(&err); + if (!ctx && !err) + err = -1; + if (ctx) { + int key = 0; + struct ctx_val *ctx_val = bpf_map_lookup_elem(&ctx_map, &key); + + /* Transfer ctx to map to be freed via implicit dtor call + * on cleanup. + */ + if (ctx_val) + ctx = bpf_kptr_xchg(&ctx_val->ctx, ctx); + if (ctx) { + bpf_testmod_ctx_release(ctx); + err = -1; + } + } + return err; +} + char _license[] SEC("license") = "GPL"; -- 2.34.1